diff --git a/trulens_eval/trulens_eval/instruments.py b/trulens_eval/trulens_eval/instruments.py
index 227c4097a..87d0d67f1 100644
--- a/trulens_eval/trulens_eval/instruments.py
+++ b/trulens_eval/trulens_eval/instruments.py
@@ -807,6 +807,13 @@ def find_instrumented(f):
         # instrumented app gets unloaded, it will be evicted from this set.
         setattr(w, Instrument.APPS, weakref.WeakSet([self.app]))
 
+        # Hack for llama_index trace_method not preserving wrapped method signature.
+        if "trace_method.<locals>.decorator.<locals>.wrapper" == func.__qualname__:
+            actual_func = func.__closure__[1].cell_contents
+            func_sig = inspect.signature(actual_func)
+            func.__signature__ = func_sig
+            func.__name__ = actual_func.__name__
+
         w.__name__ = func.__name__
 
         # NOTE(piotrm): This is important; langchain checks signatures to adjust